Island Raises $400 Million at $6.4 Billion Valuation

Island raised $400 million in a Series F round that values the enterprise security startup at $6.4 billion, the company said Thursday, more than doubling its valuation since 2024.

Evolution Equity Partners led the round, according to Island's announcement. Existing backers Prysm Capital, Sequoia Capital, Coatue Management, Cyberstarts, Insight Partners, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared and Squarepoint all returned. Dmitri Alperovitch, the CrowdStrike co-founder who now chairs the Silverado Policy Accelerator, joined as a new investor, putting his own money into the round rather than investing through a fund.

Island has raised more than $1 billion since it launched in 2020, SecurityWeek reported. The company now employs 1,000 people and says annual recurring revenue has doubled every year since its enterprise browser first shipped in 2022. It has not disclosed what that revenue figure actually is, which means there is no way to check whether $6.4 billion is a defensible multiple of it.

Evolution Equity Partners writes two $400 million checks in one week

Island's raise was not Evolution Equity Partners' only nine-figure security bet that week. The same investor led a separate $400 million Series G extension for Cyera, a rival data-security vendor, taking Cyera's total funding to $2.7 billion, according to Crunchbase News, which ranked the two rounds first and second among the week's ten largest. Snorkel AI's $350 million Series E and Enveda's $311 million Series E rounded out the top four.

Back-to-back four-hundred-million-dollar checks from the same firm, in the same week, in overlapping markets, is the kind of concentration that usually shows up only when a fund believes late-stage security is underpriced relative to where the rest of venture capital has pulled back. Evolution has not said whether it views Island and Cyera as complementary bets or a hedge against picking the wrong one.

What Island's browser turned into

Island launched in 2020 as what co-founder and chief executive Mike Fey called "the first Enterprise Browser," according to SecurityWeek. It has since layered on Zero Trust Network Access, device posture checks, inline data-loss prevention that can restrict clipboard use, downloads and screenshots, and guardrails meant to stop employees from pasting proprietary data into outside language models. Island now describes the combined product as an "agentic control plane for enterprises," extending the same controls to AI agents acting on a worker's behalf.

"This investment gives us even more capacity to innovate with our customers and help them safely scale AI," Fey said in the announcement. Evolution's Richard Seewald said Island "built the essential control layer for the next generation of enterprise computing."

Island was named to the CNBC Disruptor 50 list and was recognized by Frost & Sullivan as its 2026 Global Zero Trust Browser Security Company of the Year, the company said. Neither award discloses revenue, and Island has not said when, or whether, it plans to.

1. Island400 $ millions
2. Cyera400 $ millions
3. Snorkel AI350 $ millions
4. Enveda311 $ millions
5. Precision Neuroscience250 $ millions

Source: Crunchbase News, accessed 2026-09-28

For a comparable late-stage security check written the same week, see The Terminal's coverage of Cyera's $400 million round. Snorkel AI's data-labeling business, another late-stage round from the same week, is covered here.

Island has not said what it will spend the $400 million on beyond general language about accelerating growth, nor has it said when a Series G or an IPO might follow. The number to watch is the one it still has not published: actual revenue, the figure that would tell outsiders whether $6.4 billion is a multiple grounded in the business or in the momentum of the round that preceded it.